This application claims the priority of German Patent Document 199 42 836.0, filed Sep. 8, 1999, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a washer element for a wheel bolt and/or a wheel that is mounted with one end partially in a rounded cavity of a mounting hole for the wheel and with its other end supports the wheel bolt.
A washer element for a wheel nut of a motor vehicle wheel is known from French Patent Document FR-PS 1 452 053, which consists of a slit ring part. On the front side, this has a flat contact surface for the wheel nut and an opposite rounded area that is arranged in a rounded cavity that is formed to correspond of a mounted device for the wheel. A slit through the washer element causes a certain spring action when the wheel nut is tightened.
A task of the invention is to produce an improved washer element for a wheel bolt and/or a wheel nut that creates an optimally secured connection between wheel and wheel hub.
According to the invention, this task is solved by providing a washer element of the above noted type, wherein the washer element consists of a sleeve part with a rounded shaped end area and a wall that is profiled in cross section with an inner sleeve expansion and/or outer sleeve contraction.
Advantages achieved with the invention consist mainly in that a springy and elastic threaded connection is produced by the design of the washer element, which causes a secure fastening of the wheel on the wheel hub. Because of this washer element, loosening of the bolt in operation is also prevented. In addition, an expansion length is produced and the fitting precision increased.
To achieve these advantages, the washer element consists of a sleeve part with an end area that is designed so that it is rounded, whereby in cross section the sleeve part has a profiled wall with an inner sleeve expansion and/or an external sleeve contraction.
Various embodiment shapes of the washer element according to the invention are possible so that an appropriate prestress can be achieved when the bolt is tightened. Thus according to a first embodiment, the washer element consists of a profile that is c-shaped in cross section, whereby a partial inner sleeve expansion is provided that is designed with a narrowed collar opposite the rounded end area.
In addition, the inside sleeve expansion can be designed with a cylinder shape, whereby the end areas form collars turned inward toward the bolt shaft and one collar forms the rounded end area.
According to another embodiment it is also possible that the inner sleeve expansion is designed with a cone shape and the smaller diameter of the cone lies in the rounded end area, while the other end area forms a collar turned inward toward the bolt shaft and supports the bolt.
In addition, according to the invention, it can be provided that the sleeve recess of the washer element consists of at least one outside ring groove and that this is located between a collar turned outward and the rounded end area.
Further, the washer element can also consist of a cylindrical sleeve part on which the rounded end area connects with a collar turned inward. According to a first embodiment, the cylindrical sleeve part is provided on the inside with an expansion, whereby in another embodiment the cylindrical sleeve part is decreased in the wall on the inside and outside and an inside expansion and an outside contraction results.
All the embodiments of the washer elements have a rounded end area that lies in a correspondingly rounded cavity of the wheel and thus also achieves precise centering of the wheel.
The washer elements preferably consist of a steel material and lie with their rounded end area, say for an aluminum wheel, with the entire rounded surface area of the washer element of the washer element in a corresponding cavity of the wheel. In contrast with a steel wheel, only a smaller surface area of the rounded end area of the washer element contacts the cavity of the wheel.
The spring prestress that is achieved when the threaded bolt is installed is mainly achieved by the shape of the washer element, whereby the embodiment with a c-shaped profile causes a greater spring prestress than the cylindrical versions of the washer element.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.